Regiment/Squadron insignia

I made some of my own squad insignia and badges and put them in the Regiments folder in my game folder, but I don't seem them available to use in the game. The images are .bmp format and flat etc. etc. What did I miss and what do I do to be able to use them? I wanted to use them on 109s and RAF aircraft.

It's been a long time since I played with this stuff, but IIRC it has to be 256 colour .bmp format with exactly the same dimensions as the standard insignia and no spaces or non-alphanumeric characters in the file name. Or do as REDsWINGer suggests.